// Copyright (c) 1997  ETH Zurich (Switzerland).
// All rights reserved.
//
// This file is part of CGAL (www.cgal.org).
// You can redistribute it and/or modify it under the terms of the GNU
// General Public License as published by the Free Software Foundation,
// either version 3 of the License, or (at your option) any later version.
//
// Licensees holding a valid commercial license may use this file in
// accordance with the commercial license agreement provided with the software.
//
// This file is provided AS IS with NO WARRANTY OF ANY KIND, INCLUDING THE
// WARRANTY OF DESIGN, MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE.
//
// $URL: svn+ssh://scm.gforge.inria.fr/svn/cgal/branches/next/Polyhedron_IO/include/CGAL/IO/Polyhedron_scan_OFF.h $
// $Id: Polyhedron_scan_OFF.h 67117 2012-01-13 18:14:48Z lrineau $
// 
//
// Author(s)     : Lutz Kettner  <kettner@mpi-sb.mpg.de>

#ifndef CGAL_IO_POLYHEDRON_SCAN_OFF_H
#define CGAL_IO_POLYHEDRON_SCAN_OFF_H 1

#include <CGAL/basic.h>
#include <CGAL/IO/File_header_OFF.h>
#include <CGAL/IO/File_scanner_OFF.h>
#include <CGAL/Modifier_base.h>
#include <CGAL/Polyhedron_incremental_builder_3.h>
#include <CGAL/Polyhedron_3.h>
#include <iostream>
#include <cstddef>

namespace CGAL {

template < class HDS>
class Polyhedron_scan_OFF :  public Modifier_base<HDS> {
protected:
    std::istream&    m_in;
    File_header_OFF  m_file_header;
public:

    typedef HDS Halfedge_data_structure;

// DEFINITION
//
// Polyhedron_scan_OFF<Traits> is a polyhedral surface builder.
// It scans a polyhedron given in OFF from a stream and appends it
// incrementally using the incremental builder.

    Polyhedron_scan_OFF( std::istream& in, bool verbose = false)
        : m_in(in), m_file_header( verbose) {}

    // Activation
    void operator()( HDS& hds);

    const File_header_OFF&  header() const { return m_file_header; }
};

template < class HDS >
void
Polyhedron_scan_OFF<HDS>:: operator()( HDS& target) {
    File_scanner_OFF scanner( m_in, m_file_header.verbose());
    if ( ! m_in) {
        if ( scanner.verbose()) {
            std::cerr << " " << std::endl;
            std::cerr << "Polyhedron_scan_OFF<HDS>::" << std::endl;
            std::cerr << "operator(): input error: file format is not in "
                         "OFF." << std::endl;
        }
        return;
    }
    m_file_header = scanner;  // Remember file header after return.

    Polyhedron_incremental_builder_3<HDS> B( target, scanner.verbose());
    B.begin_surface( scanner.size_of_vertices(),
                     scanner.size_of_facets(),
                     scanner.size_of_halfedges());

    typedef typename HDS::Traits     Traits;
    typedef typename Traits::Point_3 Point;

    // read in all vertices
    std::size_t  i;
    for ( i = 0; i < scanner.size_of_vertices(); i++) {
        Point p;
        file_scan_vertex( scanner, p);
        B.add_vertex( p);
        scanner.skip_to_next_vertex( i);
    }
    if ( ! m_in  || B.error()) {
        B.rollback();
        m_in.clear( std::ios::badbit);
        return;
    }

    // read in all facets
    for ( i = 0; i < scanner.size_of_facets(); i++) {
        B.begin_facet();
        std::size_t no;
        scanner.scan_facet( no, i);
        if( ! m_in || B.error() || no < 3) {
            if ( scanner.verbose()) {
                std::cerr << " " << std::endl;
                std::cerr << "Polyhedron_scan_OFF<Traits>::" << std::endl;
                std::cerr << "operator()(): input error: facet " << i
                     << " has less than 3 vertices." << std::endl;
            }
            B.rollback();
            m_in.clear( std::ios::badbit);
            return;
        }
        for ( std::size_t j = 0; j < no; j++) {
            std::size_t index;
            scanner.scan_facet_vertex_index( index, i);
            B.add_vertex_to_facet( index);
        }
        B.end_facet();
        scanner.skip_to_next_facet( i);
    }
    if ( ! m_in  || B.error()) {
        B.rollback();
        m_in.clear( std::ios::badbit);
        return;
    }
    if ( B.check_unconnected_vertices()) {
        if ( ! B.remove_unconnected_vertices()) {
            if ( scanner.verbose()) {
                std::cerr << " " << std::endl;
                std::cerr << "Polyhedron_scan_OFF<Traits>::" << std::endl;
                std::cerr << "operator()(): input error: cannot "
                             "successfully remove isolated vertices."
                          << std::endl;
            }
            B.rollback();
            m_in.clear( std::ios::badbit);
            return;
        }
    }
    B.end_surface();
}

} //namespace CGAL
#endif // CGAL_IO_POLYHEDRON_SCAN_OFF_H //
// EOF //
